Data security in cloud computing and outsourced databases

We introduce a model for provable data possession (PDP) that allows a client that has stored data at an untrusted server to verify that the server possesses the original data without retrieving it. The model generates probabilistic proofs of possession by sampling random sets of blocks from the server, which drastically reduces I/O costs. The client maintains a constant amount of metadata to verify the proof. The challenge/response protocol transmits a small, constant amount of data, which minimizes network communication. Thus, the PDP model for remote data checking supports large data sets in widely distributed storage systems. It is also superior in performance by minimizing the use of expensive public-key cryptography in metadata management. We present the architecture and implementation of various SHAROES components and our experiments demonstrate performance superior to other proposals by over 40% on a number of benchmarks.